Sentinel node mapping and biopsy in thyroid cancer: a surgical perspective

Area of Science:

• Oncology
• Nuclear Medicine
• Surgical Pathology

Background:

• The prognostic significance of nodal disease in differentiated thyroid cancer (DTC) is debated.
• Sentinel node biopsy (SNB) is an evolving technique for staging thyroid cancer.
• Preoperative clinical and ultrasound assessments may not detect subclinical lymph node involvement.

Purpose of the Study:

• To evaluate the efficacy of radiocolloid lymphoscintigraphy and gamma probe for SNB in DTC patients.
• To assess the potential clinical role of SNB in managing DTC with small tumors.
• To determine the detection rate of lymph node metastasis in clinically node-negative DTC.

Main Methods:

• Forty-one patients with suspected DTC and no clinical/ultrasound lymph node evidence underwent SNB.
• Intratumoral injection of 99mTc-nanocolloid followed by dynamic lymphoscintigraphy.
• Excision of identified sentinel lymph nodes (SLNs) using a handheld gamma probe; frozen section analysis.

Main Results:

• Lymphoscintigraphy successfully visualized SLNs in all patients.
• Metastatic lymph nodes were found in 21 out of 40 patients (over 50%), often with micrometastases.
• SNB identified metastatic disease even when preoperative imaging was negative.

Conclusions:

• Radiocolloid lymphoscintigraphy and gamma probe-guided SNB are highly sensitive for SLN detection in DTC.
• SNB effectively identifies occult lymph node metastases in clinically node-negative DTC patients.
• This technique may serve as a valuable tool for guiding lymphadenectomy decisions in early-stage DTC.